Because of the possibility of spreading infectious disease, hypodermic needles used in the health care industry are generally disposed of after a single use. The need to prevent repuncture with used hypodermic needles has become of paramount importance in view of the AIDS epidemic. Patients, doctors, nurses, lab personnel, and hospital laundry workers have become accidentally infected with the AIDS HIV virus by puncturing themselves with hypodermic needles previously used on AIDS infected patients. Although provisions are made for the safe disposal of hypodermic needles in the medical workplace, the difficult and sometimes chaotic environment of some medical situations can cause even the best trained medical personnel to misplace a used hypodermic needle.
Because the hypodermic needle is frequently used during times of high stress, it would be of great benefit to provide a needle that automatically shields itself after a single use without the necessity of any conscious effort or thought by the attendant using the needle.
Many different protective cap-type, or sheath-type devices for protecting hypodermic needles against accidental needle sticks have been advanced. While many of these devices are workable, they either require manual deployment of a protective cap or sheath, (and thus a conscious effort by the attendant) or they involve a mechanism that obstructs the attendant's view of the needle as it is advanced into the patient's skin. Other shielding devices that are available involve complex mechanisms which would be costly to manufacture. U.S. Pat. No. 4,915,696 to Feimer, U.S. Pat. No. 4,725,267 to Vaillancourt, U.S. Pat. No. 4,986,819 to Sobel, U.S. Pat. No. 4,892,521 to Laico, U.S. Pat. No. 4,846,809 to Sims U.S. Pat. No. 4,943,284 to Erlich, U.S. Pat. No. 4,911,694 to Dolan, and U.S. Pat. No. 5,015,240 to Soproni are representative of devices which require manual deployment of a trigger, or of a protective cap or sheath by the attendant. These devices do not address the need for automatic actuation of the cap to eliminate the element of human error in deployment of the protective device.
Some prior inventions obstruct the vision of a substantial portion of the needle when entering the patient's skin, and require a specific amount of insertion into the skin to effect the triggering of the protective device, (e.g. U.S. Pat. No. 4,795,432 to Karczmer and U.S. Pat. No. 5,059,180 to McLees). These type of devices would be inconvenient to use and deploy, and possibly dangerous.
It is an object, therefore, of the present invention to provide a needle tip protective guard for a hypodermic needle that operates automatically and that requires no additional action by the operator.
It is another object of the invention to provide a needle guard having a short, unobtrusive profile in the retracted, inactivated position.
It is a further object of the invention to provide a needle tip guard which includes a propellent system for placing the guard, which propellent system becomes activated when the operator presses the plunger on the hypodermic syringe to complete the injection. Thus, the act of using the syringe causes the guard to operate.
It is another object to provide a needle guard that will close itself off to prohibit the needle from reemerging once it has been enclosed by the guard.
Another object is to provide a needle guard that is made integral with the needle, so that the needle and guard are mounted to the syringe simultaneously.
A still further object of the invention is to provide such a guard mechanism that is constructed of simple plastic parts to minimize material and production costs.